24.3.5 Receiving a Break Character

The EUSART module can receive a Break character in two ways.

The first method to detect a Break character uses the Framing Error (FERR) bit and the received data as indicated by RCxREG. The Baud Rate Generator is assumed to have been initialized to the expected baud rate.

A Break character has been received when all three of the following conditions are true:

  • RCxIF bit is set
  • FERR bit is set
  • RCxREG = 00h

The second method uses the Auto-Wake-Up feature described in Auto-Wake-Up on Break. By enabling this feature, the EUSART will sample the next two transitions on RX/DT, cause an RCxIF interrupt, and receive the next data byte followed by another interrupt.

Note that following a Break character, the user will typically want to enable the Auto-Baud Detect feature. For both methods, the user can set the ABDEN bit before placing the EUSART in Sleep mode.

Figure 24-9. Send Break Character Sequence